1. Field of the Invention
The present invention relates generally to organic fertilizer production and, more particularly, to a process and equipment for producing unpolluting organic fertilizer from waste matter such as garbage and sewage.
According to the present invention, the waste matter can be easily treated at low cost and without causing environmental pollution, thereby providing unpolluting organic fertilizer.
The thus produced organic fertilizer can be stored over extended periods of time and, being buried in the ground, is decomposed and so taken in by in plants.
2. Description of Related Art
In the past, garbage as from a market or kitchen has been incinerated at elevated temperatures of about 750.degree. to 950.degree. C. in a certain garbage disposal system and, simultaneously with this, bad-smelling air has been burned. Toxic gases generated by incineration are removed by an attachment, and so are not discharged from the garbage disposal system. The resulting ash is carried to a given place for reclamation.
FIG. 3 illustrates a typical example of conventional waste matter disposal equipment. As illustrated, a batch of the waste matter is fed in a tank 100, in which it is crushed by a crusher 102, and it is carried therefrom into a storage tank 104. In this tank 104, the waste matter is treated by a centrifuge 106, and is then fed to a regulator tank 108. The thus centrifuged waste matter is incinerated in an incinerator system 110.
The liquid waste matter in the tank 108 is mixed with air in a spray oxidization tank 112 and a catalytic oxidizer 114, fed into an aerobic oxidization tank 116 in which it is converted into a form that is easily digestible by bacteria, and then fed into an aerator 118 in which it is oxidized (or corroded) by oxygen and bacteria.
The thus oxidized liquid waste water is fed into a sedimentation tank 120 for finer matter removal, sterilized by a chlorine sterilizer 122, and finally diluted with much water for draining into rivers, etc.
Year by year, there is a remarkable increase in the amount of garbage thrown away, and this has already become a social problem in large cities and their surroundings.
However, much difficulty has been experienced in building new incineration installations, thanks to skyrocketing land rents, trouble in locating building sites, and environmental problems. Even when building sites are located, there is a new problem as to where the incinerated waste matter will be stored.
Moreover, since conventional sewage disposal installations are very large, it is very difficult to build up them at new locations, because of skyrocketing land rents and difficulty in securing building sites. To add to this, since conventional disposal installations need much water for sewage treatment, some severe limitation is now imposed on the conditions of location; for instance, such installations must be located near rivers. Even when such location is secured, it is difficult to construct such installations.
It is generally said that rivers have a self-cleaning action when suspended solids are within 5 ppm. However, since the current standard for effluent from sewage disposal systems is within 40 ppm in terms of suspended solids (in Tokyo Metropolis), rivers, gulfs and seawater are much more polluted, if effluents having such large suspended solids are discharged.
In view of the situations as mentioned above, an object of the invention is to provide a system and process for producing organic fertilizer which can treat waste matter such as garbage and sewage on a smaller scale and at lower cost than ever before, and without causing environmental pollution, thereby producing unpolluting organic fertilizer that can be used as a land improver as well.